Climbing is recognized as a particularly effective type of aerobic exercise, and as a result, exercise machines facilitating this type of exercise are popular for both home and health club use. There have been a variety of approaches taken in designing stair climbing apparatus as illustrated in U.S. Pat. Nos. 3,497,215, 4,687,195, 5,135,447, 5,180,351, 5,195,935, 5,222,928, 5,238,462, 5,318,487, 5,403,252, 6,855,093, 7,153,238 and Re. 34,959 as well as PCT application WO/94/02214. Typically these machines utilize a pair of pedals which are adapted for vertical reciprocating motion to provide a user who is standing on the pedals with a simulated climbing exercise. The vertical reciprocating motion is generally translated into a rotary motion by a suitable system of belts, gears and clutches, for example. The rotary motion that is imparted to a shaft, flywheel or the like is usually opposed by a variable source of resistance force, typically an alternator, eddy current break or the like that is responsive to a control signal for selectively varying the level of resistance. Also, it is not unusual to include features such as controlling and monitoring the speed of the pedals by the operator or by computer programs. Other approaches additionally provide for an upper body workout. For example, many health clubs have climbing walls. Another example is the Versa Climber apparatus sold by Heart Rate, Inc. of Costa Mesa, Calif. which is a mechanical hydraulic device that along with pedals provides a set of movable handholds for an upper body workout.